Merge branch 'master' of /home/tridge/samba/git/combined
[Samba/aatanasov.git] / source3 / libads / kerberos_verify.c
blob8502902963114336c65ff1cbcc78b8359b974d4c
1 /*
2 Unix SMB/CIFS implementation.
3 kerberos utility library
4 Copyright (C) Andrew Tridgell 2001
5 Copyright (C) Remus Koos 2001
6 Copyright (C) Luke Howard 2003
7 Copyright (C) Guenther Deschner 2003, 2005
8 Copyright (C) Jim McDonough (jmcd@us.ibm.com) 2003
9 Copyright (C) Andrew Bartlett <abartlet@samba.org> 2004-2005
10 Copyright (C) Jeremy Allison 2007
12 This program is free software; you can redistribute it and/or modify
13 it under the terms of the GNU General Public License as published by
14 the Free Software Foundation; either version 3 of the License, or
15 (at your option) any later version.
17 This program is distributed in the hope that it will be useful,
18 but WITHOUT ANY WARRANTY; without even the implied warranty of
19 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
20 GNU General Public License for more details.
22 You should have received a copy of the GNU General Public License
23 along with this program. If not, see <http://www.gnu.org/licenses/>.
26 #include "includes.h"
28 #ifdef HAVE_KRB5
30 #if !defined(HAVE_KRB5_PRINC_COMPONENT)
31 const krb5_data *krb5_princ_component(krb5_context, krb5_principal, int );
32 #endif
34 static bool ads_dedicated_keytab_verify_ticket(krb5_context context,
35 krb5_auth_context auth_context,
36 const DATA_BLOB *ticket,
37 krb5_ticket **pp_tkt,
38 krb5_keyblock **keyblock,
39 krb5_error_code *perr)
41 krb5_error_code ret = 0;
42 bool auth_ok = false;
43 krb5_keytab keytab = NULL;
44 krb5_keytab_entry kt_entry;
45 krb5_ticket *dec_ticket = NULL;
47 krb5_data packet;
48 krb5_kvno kvno = 0;
49 krb5_enctype enctype;
51 *pp_tkt = NULL;
52 *keyblock = NULL;
53 *perr = 0;
55 ZERO_STRUCT(kt_entry);
57 ret = smb_krb5_open_keytab(context, lp_dedicated_keytab_file(), true,
58 &keytab);
59 if (ret) {
60 DEBUG(1, ("smb_krb5_open_keytab failed (%s)\n",
61 error_message(ret)));
62 goto out;
65 packet.length = ticket->length;
66 packet.data = (char *)ticket->data;
68 ret = krb5_rd_req(context, &auth_context, &packet, NULL, keytab,
69 NULL, &dec_ticket);
70 if (ret) {
71 DEBUG(0, ("krb5_rd_req failed (%s)\n", error_message(ret)));
72 goto out;
75 #ifdef HAVE_ETYPE_IN_ENCRYPTEDDATA /* Heimdal */
76 enctype = dec_ticket->ticket.key.keytype;
77 #else /* MIT */
78 enctype = dec_ticket->enc_part.enctype;
79 kvno = dec_ticket->enc_part.kvno;
80 #endif
82 /* Get the key for checking the pac signature */
83 ret = krb5_kt_get_entry(context, keytab, dec_ticket->server,
84 kvno, enctype, &kt_entry);
85 if (ret) {
86 DEBUG(0, ("krb5_kt_get_entry failed (%s)\n",
87 error_message(ret)));
88 goto out;
91 ret = krb5_copy_keyblock(context, KRB5_KT_KEY(&kt_entry), keyblock);
92 smb_krb5_kt_free_entry(context, &kt_entry);
94 if (ret) {
95 DEBUG(0, ("failed to copy key: %s\n",
96 error_message(ret)));
97 goto out;
100 auth_ok = true;
101 *pp_tkt = dec_ticket;
102 dec_ticket = NULL;
104 out:
105 if (dec_ticket)
106 krb5_free_ticket(context, dec_ticket);
108 if (keytab)
109 krb5_kt_close(context, keytab);
111 *perr = ret;
112 return auth_ok;
115 /**********************************************************************************
116 Try to verify a ticket using the system keytab... the system keytab has kvno -1 entries, so
117 it's more like what microsoft does... see comment in utils/net_ads.c in the
118 ads_keytab_add_entry function for details.
119 ***********************************************************************************/
121 static bool ads_keytab_verify_ticket(krb5_context context,
122 krb5_auth_context auth_context,
123 const DATA_BLOB *ticket,
124 krb5_ticket **pp_tkt,
125 krb5_keyblock **keyblock,
126 krb5_error_code *perr)
128 krb5_error_code ret = 0;
129 bool auth_ok = False;
130 krb5_keytab keytab = NULL;
131 krb5_kt_cursor kt_cursor;
132 krb5_keytab_entry kt_entry;
133 char *valid_princ_formats[7] = { NULL, NULL, NULL, NULL, NULL, NULL, NULL };
134 char *entry_princ_s = NULL;
135 fstring my_name, my_fqdn;
136 int i;
137 int number_matched_principals = 0;
138 krb5_data packet;
140 *pp_tkt = NULL;
141 *keyblock = NULL;
142 *perr = 0;
144 /* Generate the list of principal names which we expect
145 * clients might want to use for authenticating to the file
146 * service. We allow name$,{host,cifs}/{name,fqdn,name.REALM}. */
148 fstrcpy(my_name, global_myname());
150 my_fqdn[0] = '\0';
151 name_to_fqdn(my_fqdn, global_myname());
153 if (asprintf(&valid_princ_formats[0], "%s$@%s", my_name, lp_realm()) == -1) {
154 goto out;
156 if (asprintf(&valid_princ_formats[1], "host/%s@%s", my_name, lp_realm()) == -1) {
157 goto out;
159 if (asprintf(&valid_princ_formats[2], "host/%s@%s", my_fqdn, lp_realm()) == -1) {
160 goto out;
162 if (asprintf(&valid_princ_formats[3], "host/%s.%s@%s", my_name, lp_realm(), lp_realm()) == -1) {
163 goto out;
165 if (asprintf(&valid_princ_formats[4], "cifs/%s@%s", my_name, lp_realm()) == -1) {
166 goto out;
168 if (asprintf(&valid_princ_formats[5], "cifs/%s@%s", my_fqdn, lp_realm()) == -1) {
169 goto out;
171 if (asprintf(&valid_princ_formats[6], "cifs/%s.%s@%s", my_name, lp_realm(), lp_realm()) == -1) {
172 goto out;
175 ZERO_STRUCT(kt_entry);
176 ZERO_STRUCT(kt_cursor);
178 ret = smb_krb5_open_keytab(context, NULL, False, &keytab);
179 if (ret) {
180 DEBUG(1, ("ads_keytab_verify_ticket: smb_krb5_open_keytab failed (%s)\n", error_message(ret)));
181 goto out;
184 /* Iterate through the keytab. For each key, if the principal
185 * name case-insensitively matches one of the allowed formats,
186 * try verifying the ticket using that principal. */
188 ret = krb5_kt_start_seq_get(context, keytab, &kt_cursor);
189 if (ret) {
190 DEBUG(1, ("ads_keytab_verify_ticket: krb5_kt_start_seq_get failed (%s)\n", error_message(ret)));
191 goto out;
194 while (!auth_ok && (krb5_kt_next_entry(context, keytab, &kt_entry, &kt_cursor) == 0)) {
195 ret = smb_krb5_unparse_name(talloc_tos(), context, kt_entry.principal, &entry_princ_s);
196 if (ret) {
197 DEBUG(1, ("ads_keytab_verify_ticket: smb_krb5_unparse_name failed (%s)\n",
198 error_message(ret)));
199 goto out;
202 for (i = 0; i < ARRAY_SIZE(valid_princ_formats); i++) {
204 if (!strequal(entry_princ_s, valid_princ_formats[i])) {
205 continue;
208 number_matched_principals++;
209 packet.length = ticket->length;
210 packet.data = (char *)ticket->data;
211 *pp_tkt = NULL;
213 ret = krb5_rd_req_return_keyblock_from_keytab(context, &auth_context, &packet,
214 kt_entry.principal, keytab,
215 NULL, pp_tkt, keyblock);
217 if (ret) {
218 DEBUG(10,("ads_keytab_verify_ticket: "
219 "krb5_rd_req_return_keyblock_from_keytab(%s) failed: %s\n",
220 entry_princ_s, error_message(ret)));
222 /* workaround for MIT:
223 * as krb5_ktfile_get_entry will explicitly
224 * close the krb5_keytab as soon as krb5_rd_req
225 * has successfully decrypted the ticket but the
226 * ticket is not valid yet (due to clockskew)
227 * there is no point in querying more keytab
228 * entries - Guenther */
230 if (ret == KRB5KRB_AP_ERR_TKT_NYV ||
231 ret == KRB5KRB_AP_ERR_TKT_EXPIRED ||
232 ret == KRB5KRB_AP_ERR_SKEW) {
233 break;
235 } else {
236 DEBUG(3,("ads_keytab_verify_ticket: "
237 "krb5_rd_req_return_keyblock_from_keytab succeeded for principal %s\n",
238 entry_princ_s));
239 auth_ok = True;
240 break;
244 /* Free the name we parsed. */
245 TALLOC_FREE(entry_princ_s);
247 /* Free the entry we just read. */
248 smb_krb5_kt_free_entry(context, &kt_entry);
249 ZERO_STRUCT(kt_entry);
251 krb5_kt_end_seq_get(context, keytab, &kt_cursor);
253 ZERO_STRUCT(kt_cursor);
255 out:
257 for (i = 0; i < ARRAY_SIZE(valid_princ_formats); i++) {
258 SAFE_FREE(valid_princ_formats[i]);
261 if (!auth_ok) {
262 if (!number_matched_principals) {
263 DEBUG(3, ("ads_keytab_verify_ticket: no keytab principals matched expected file service name.\n"));
264 } else {
265 DEBUG(3, ("ads_keytab_verify_ticket: krb5_rd_req failed for all %d matched keytab principals\n",
266 number_matched_principals));
270 SAFE_FREE(entry_princ_s);
273 krb5_keytab_entry zero_kt_entry;
274 ZERO_STRUCT(zero_kt_entry);
275 if (memcmp(&zero_kt_entry, &kt_entry, sizeof(krb5_keytab_entry))) {
276 smb_krb5_kt_free_entry(context, &kt_entry);
281 krb5_kt_cursor zero_csr;
282 ZERO_STRUCT(zero_csr);
283 if ((memcmp(&kt_cursor, &zero_csr, sizeof(krb5_kt_cursor)) != 0) && keytab) {
284 krb5_kt_end_seq_get(context, keytab, &kt_cursor);
288 if (keytab) {
289 krb5_kt_close(context, keytab);
291 *perr = ret;
292 return auth_ok;
295 /**********************************************************************************
296 Try to verify a ticket using the secrets.tdb.
297 ***********************************************************************************/
299 static krb5_error_code ads_secrets_verify_ticket(krb5_context context,
300 krb5_auth_context auth_context,
301 krb5_principal host_princ,
302 const DATA_BLOB *ticket,
303 krb5_ticket **pp_tkt,
304 krb5_keyblock **keyblock,
305 krb5_error_code *perr)
307 krb5_error_code ret = 0;
308 bool auth_ok = False;
309 char *password_s = NULL;
310 krb5_data password;
311 krb5_enctype enctypes[] = {
312 #if defined(ENCTYPE_ARCFOUR_HMAC)
313 ENCTYPE_ARCFOUR_HMAC,
314 #endif
315 ENCTYPE_DES_CBC_CRC,
316 ENCTYPE_DES_CBC_MD5,
317 ENCTYPE_NULL
319 krb5_data packet;
320 int i;
322 *pp_tkt = NULL;
323 *keyblock = NULL;
324 *perr = 0;
327 if (!secrets_init()) {
328 DEBUG(1,("ads_secrets_verify_ticket: secrets_init failed\n"));
329 *perr = KRB5_CONFIG_CANTOPEN;
330 return False;
333 password_s = secrets_fetch_machine_password(lp_workgroup(), NULL, NULL);
334 if (!password_s) {
335 DEBUG(1,("ads_secrets_verify_ticket: failed to fetch machine password\n"));
336 *perr = KRB5_LIBOS_CANTREADPWD;
337 return False;
340 password.data = password_s;
341 password.length = strlen(password_s);
343 /* CIFS doesn't use addresses in tickets. This would break NAT. JRA */
345 packet.length = ticket->length;
346 packet.data = (char *)ticket->data;
348 /* We need to setup a auth context with each possible encoding type in turn. */
349 for (i=0;enctypes[i];i++) {
350 krb5_keyblock *key = NULL;
352 if (!(key = SMB_MALLOC_P(krb5_keyblock))) {
353 ret = ENOMEM;
354 goto out;
357 if (create_kerberos_key_from_string(context, host_princ, &password, key, enctypes[i], false)) {
358 SAFE_FREE(key);
359 continue;
362 krb5_auth_con_setuseruserkey(context, auth_context, key);
364 if (!(ret = krb5_rd_req(context, &auth_context, &packet,
365 NULL,
366 NULL, NULL, pp_tkt))) {
367 DEBUG(10,("ads_secrets_verify_ticket: enc type [%u] decrypted message !\n",
368 (unsigned int)enctypes[i] ));
369 auth_ok = True;
370 krb5_copy_keyblock(context, key, keyblock);
371 krb5_free_keyblock(context, key);
372 break;
375 DEBUG((ret != KRB5_BAD_ENCTYPE) ? 3 : 10,
376 ("ads_secrets_verify_ticket: enc type [%u] failed to decrypt with error %s\n",
377 (unsigned int)enctypes[i], error_message(ret)));
379 /* successfully decrypted but ticket is just not valid at the moment */
380 if (ret == KRB5KRB_AP_ERR_TKT_NYV ||
381 ret == KRB5KRB_AP_ERR_TKT_EXPIRED ||
382 ret == KRB5KRB_AP_ERR_SKEW) {
383 krb5_free_keyblock(context, key);
384 break;
387 krb5_free_keyblock(context, key);
391 out:
392 SAFE_FREE(password_s);
393 *perr = ret;
394 return auth_ok;
397 /**********************************************************************************
398 Verify an incoming ticket and parse out the principal name and
399 authorization_data if available.
400 ***********************************************************************************/
402 NTSTATUS ads_verify_ticket(TALLOC_CTX *mem_ctx,
403 const char *realm,
404 time_t time_offset,
405 const DATA_BLOB *ticket,
406 char **principal,
407 struct PAC_DATA **pac_data,
408 DATA_BLOB *ap_rep,
409 DATA_BLOB *session_key,
410 bool use_replay_cache)
412 NTSTATUS sret = NT_STATUS_LOGON_FAILURE;
413 NTSTATUS pac_ret;
414 DATA_BLOB auth_data;
415 krb5_context context = NULL;
416 krb5_auth_context auth_context = NULL;
417 krb5_data packet;
418 krb5_ticket *tkt = NULL;
419 krb5_rcache rcache = NULL;
420 krb5_keyblock *keyblock = NULL;
421 time_t authtime;
422 krb5_error_code ret = 0;
423 int flags = 0;
424 krb5_principal host_princ = NULL;
425 krb5_const_principal client_principal = NULL;
426 char *host_princ_s = NULL;
427 bool auth_ok = False;
428 bool got_auth_data = False;
429 struct named_mutex *mutex = NULL;
431 ZERO_STRUCT(packet);
432 ZERO_STRUCT(auth_data);
434 *principal = NULL;
435 *pac_data = NULL;
436 *ap_rep = data_blob_null;
437 *session_key = data_blob_null;
439 initialize_krb5_error_table();
440 ret = krb5_init_context(&context);
441 if (ret) {
442 DEBUG(1,("ads_verify_ticket: krb5_init_context failed (%s)\n", error_message(ret)));
443 return NT_STATUS_LOGON_FAILURE;
446 if (time_offset != 0) {
447 krb5_set_real_time(context, time(NULL) + time_offset, 0);
450 ret = krb5_set_default_realm(context, realm);
451 if (ret) {
452 DEBUG(1,("ads_verify_ticket: krb5_set_default_realm failed (%s)\n", error_message(ret)));
453 goto out;
456 /* This whole process is far more complex than I would
457 like. We have to go through all this to allow us to store
458 the secret internally, instead of using /etc/krb5.keytab */
460 ret = krb5_auth_con_init(context, &auth_context);
461 if (ret) {
462 DEBUG(1,("ads_verify_ticket: krb5_auth_con_init failed (%s)\n", error_message(ret)));
463 goto out;
466 krb5_auth_con_getflags( context, auth_context, &flags );
467 if ( !use_replay_cache ) {
468 /* Disable default use of a replay cache */
469 flags &= ~KRB5_AUTH_CONTEXT_DO_TIME;
470 krb5_auth_con_setflags( context, auth_context, flags );
473 if (asprintf(&host_princ_s, "%s$", global_myname()) == -1) {
474 goto out;
477 strlower_m(host_princ_s);
478 ret = smb_krb5_parse_name(context, host_princ_s, &host_princ);
479 if (ret) {
480 DEBUG(1,("ads_verify_ticket: smb_krb5_parse_name(%s) failed (%s)\n",
481 host_princ_s, error_message(ret)));
482 goto out;
486 if ( use_replay_cache ) {
488 /* Lock a mutex surrounding the replay as there is no
489 locking in the MIT krb5 code surrounding the replay
490 cache... */
492 mutex = grab_named_mutex(talloc_tos(), "replay cache mutex",
493 10);
494 if (mutex == NULL) {
495 DEBUG(1,("ads_verify_ticket: unable to protect "
496 "replay cache with mutex.\n"));
497 ret = KRB5_CC_IO;
498 goto out;
501 /* JRA. We must set the rcache here. This will prevent
502 replay attacks. */
504 ret = krb5_get_server_rcache(context,
505 krb5_princ_component(context, host_princ, 0),
506 &rcache);
507 if (ret) {
508 DEBUG(1,("ads_verify_ticket: krb5_get_server_rcache "
509 "failed (%s)\n", error_message(ret)));
510 goto out;
513 ret = krb5_auth_con_setrcache(context, auth_context, rcache);
514 if (ret) {
515 DEBUG(1,("ads_verify_ticket: krb5_auth_con_setrcache "
516 "failed (%s)\n", error_message(ret)));
517 goto out;
521 switch (lp_kerberos_method()) {
522 default:
523 case KERBEROS_VERIFY_SECRETS:
524 auth_ok = ads_secrets_verify_ticket(context, auth_context,
525 host_princ, ticket, &tkt, &keyblock, &ret);
526 break;
527 case KERBEROS_VERIFY_SYSTEM_KEYTAB:
528 auth_ok = ads_keytab_verify_ticket(context, auth_context,
529 ticket, &tkt, &keyblock, &ret);
530 break;
531 case KERBEROS_VERIFY_DEDICATED_KEYTAB:
532 auth_ok = ads_dedicated_keytab_verify_ticket(context,
533 auth_context, ticket, &tkt, &keyblock, &ret);
534 break;
535 case KERBEROS_VERIFY_SECRETS_AND_KEYTAB:
536 /* First try secrets.tdb and fallback to the krb5.keytab if
537 necessary. This is the pre 3.4 behavior when
538 "use kerberos keytab" was true.*/
539 auth_ok = ads_secrets_verify_ticket(context, auth_context,
540 host_princ, ticket, &tkt, &keyblock, &ret);
542 if (!auth_ok) {
543 /* Only fallback if we failed to decrypt the ticket */
544 if (ret != KRB5KRB_AP_ERR_TKT_NYV &&
545 ret != KRB5KRB_AP_ERR_TKT_EXPIRED &&
546 ret != KRB5KRB_AP_ERR_SKEW) {
547 auth_ok = ads_keytab_verify_ticket(context,
548 auth_context, ticket, &tkt, &keyblock,
549 &ret);
552 break;
555 if ( use_replay_cache ) {
556 TALLOC_FREE(mutex);
557 #if 0
558 /* Heimdal leaks here, if we fix the leak, MIT crashes */
559 if (rcache) {
560 krb5_rc_close(context, rcache);
562 #endif
565 if (!auth_ok) {
566 DEBUG(3,("ads_verify_ticket: krb5_rd_req with auth failed (%s)\n",
567 error_message(ret)));
568 /* Try map the error return in case it's something like
569 * a clock skew error.
571 sret = krb5_to_nt_status(ret);
572 if (NT_STATUS_IS_OK(sret) || NT_STATUS_EQUAL(sret,NT_STATUS_UNSUCCESSFUL)) {
573 sret = NT_STATUS_LOGON_FAILURE;
575 DEBUG(10,("ads_verify_ticket: returning error %s\n",
576 nt_errstr(sret) ));
577 goto out;
580 authtime = get_authtime_from_tkt(tkt);
581 client_principal = get_principal_from_tkt(tkt);
583 ret = krb5_mk_rep(context, auth_context, &packet);
584 if (ret) {
585 DEBUG(3,("ads_verify_ticket: Failed to generate mutual authentication reply (%s)\n",
586 error_message(ret)));
587 goto out;
590 *ap_rep = data_blob(packet.data, packet.length);
591 if (packet.data) {
592 kerberos_free_data_contents(context, &packet);
593 ZERO_STRUCT(packet);
596 get_krb5_smb_session_key(context, auth_context, session_key, True);
597 dump_data_pw("SMB session key (from ticket)\n", session_key->data, session_key->length);
599 #if 0
600 file_save("/tmp/ticket.dat", ticket->data, ticket->length);
601 #endif
603 /* continue when no PAC is retrieved or we couldn't decode the PAC
604 (like accounts that have the UF_NO_AUTH_DATA_REQUIRED flag set, or
605 Kerberos tickets encrypted using a DES key) - Guenther */
607 got_auth_data = get_auth_data_from_tkt(mem_ctx, &auth_data, tkt);
608 if (!got_auth_data) {
609 DEBUG(3,("ads_verify_ticket: did not retrieve auth data. continuing without PAC\n"));
612 if (got_auth_data) {
613 pac_ret = decode_pac_data(mem_ctx, &auth_data, context, keyblock, client_principal, authtime, pac_data);
614 if (!NT_STATUS_IS_OK(pac_ret)) {
615 DEBUG(3,("ads_verify_ticket: failed to decode PAC_DATA: %s\n", nt_errstr(pac_ret)));
616 *pac_data = NULL;
618 data_blob_free(&auth_data);
621 #if 0
622 #if defined(HAVE_KRB5_TKT_ENC_PART2)
623 /* MIT */
624 if (tkt->enc_part2) {
625 file_save("/tmp/authdata.dat",
626 tkt->enc_part2->authorization_data[0]->contents,
627 tkt->enc_part2->authorization_data[0]->length);
629 #else
630 /* Heimdal */
631 if (tkt->ticket.authorization_data) {
632 file_save("/tmp/authdata.dat",
633 tkt->ticket.authorization_data->val->ad_data.data,
634 tkt->ticket.authorization_data->val->ad_data.length);
636 #endif
637 #endif
639 if ((ret = smb_krb5_unparse_name(mem_ctx, context, client_principal, principal))) {
640 DEBUG(3,("ads_verify_ticket: smb_krb5_unparse_name failed (%s)\n",
641 error_message(ret)));
642 sret = NT_STATUS_LOGON_FAILURE;
643 goto out;
646 sret = NT_STATUS_OK;
648 out:
650 TALLOC_FREE(mutex);
652 if (!NT_STATUS_IS_OK(sret)) {
653 data_blob_free(&auth_data);
656 if (!NT_STATUS_IS_OK(sret)) {
657 data_blob_free(ap_rep);
660 if (host_princ) {
661 krb5_free_principal(context, host_princ);
664 if (keyblock) {
665 krb5_free_keyblock(context, keyblock);
668 if (tkt != NULL) {
669 krb5_free_ticket(context, tkt);
672 SAFE_FREE(host_princ_s);
674 if (auth_context) {
675 krb5_auth_con_free(context, auth_context);
678 if (context) {
679 krb5_free_context(context);
682 return sret;
685 #endif /* HAVE_KRB5 */